Have both. The Strymon is an incredibly versatile and awesome sounding delay stomp. Has character, depth, all sorts of sounds, lots of them useful and very tewakable, with 100 saveable presets . Space is also very versatile, though for me not as many usable sounds for live.
On electric guitar both sound awesome. On electric violin [piezo pickup] Space sounds a bit metallic and a bit on the treble side, so I take off mostly the trebles on all presets. BUT I am very sensitive to anything that sounds at all digital, for example I do not like the line 6 delay on fiddle - sounds completely metallic to me, but this is not an issue for a lot of folks so could be just my ears
Both of them can be controlled in real time with foot pedals to shift all sorts of parameters, allows you to sort of morph within a preset
They complement one another and going through the strymon mellows Space on the fiddle
I am considering changing to another reverb that is warmer, possibly Strymon's Blue sky, as piezos and fiddles just tend toward the brittler side and the warmer the better
Someone mentioned Bricasti and this box is absolutely incredible, completely in a league of its own in reverbs, worth every penny for mixing acoustic instruments for sure
A couple of plugins that I've been demoing this week that I really like are Relab's emulation of the lexicon 480, which is the best reverb plugin I have heard, and Soundtoys echoboy delay, which i am going to have to get, it is just fabulous. The warmest most versatile tape delay i have ever heard, including hardware units and i have played echoplexes, roland space echos, sony D7, and others and is just brilliant, unbelievable depth. Probably too much depth for some mix applications as it is so rich.
PSP's 608 multi delay which just came out is also very nice and is on special this month FYI [I am not a dealer etc in any way]